That's about 63 percent more than the 20.6 million adults previously estimated in less comprehensive studies, and likely indicates that the "chiropractic first" movement touted by health experts troubled by the overuse of addictive drugs and surgery has become increasingly popular.

"Americans who have exposure to chiropractors are more likely to have an opinion of them, and in general those opinions are positive," Gallup concluded.

Among the other key findings:

* While most patients only head to a doctor of chiropractic when they're in pain, 31 percent of adults who've been treated within the last five years say they prefer regular visits -- regardless of whether they're hurting.

* Those under age 50 are likelier to say a chiropractor would be their first choice for treating back or neck pain.

* So "strongly committed" are recent users that they averaged 11 visits in the last 12 months.

"This groundbreaking report shows Americans are embracing chiropractic as an alternative to other costly and invasive treatments," said the not-for-profit Foundation for Chiropractic Progress' Sherry McAllister, DC.

Indeed, today's chiropractors -- with a minimum of 7 years of higher education, including clinical patient management -- are not only sought out for pain relief, but also for advice on healthy living, increased flexibility and injury prevention.